Strain clamp



Jfily 3, 1923.

v 2 T. H. BARNARD STRAI N CLAMP Filed Aug. 5, 1922 INVENTEIR TTY'.

E1Y J d Patented July 3, 19 23.

UNITED STATES THOMAS H. BARNARD,'OF TORONTO QNTARIO, CANADA.

s'ranm CLAMP.

Application filed August 3, 1922.. Serial No. 579,478.v

To all whom it may concern. s

Be it known that I, THOMAS H. BARNARD,

of the city ofToronto, in the county of York, Province of Ontario, Canada, a subject of the King of Great Britain, have 1nvented certain new and useful Improvements in Strain Clamps, of which the following is a specification.

' This invention relates to devices commonlycalled strain clamps which are generally used for anohorin the dead ends of electrical cables, althoug such devices are in some cases used in various combinations for supporting through cables.

My object is to devise an improved construction for this purpose, which construction may be used for securing the cable, with its armoring, in position, though in cases Where additional security is desirable, the armoring may be removed from the core adja'cent the end of the cable, and the core 1tself secured in place in a suitable manner, thus giving much greater-security.

I attain my object by means of the constructions hereinafter described and illustrated in the accompanying drawings 11]. whichf Fig. l is a longitudinal section through my improved clamp;

, Fig.2 is a plan view of the same; and

Fig. 3 a cross section through the same. 1 In the drawings like numerals of reference indicate corresponding parts in the different figures.

1 is the casing, which will usually be stamped up fromthe flat sheet into substantially channel form. Between the sides of thechannel issupported the bar 2. This bar is held in place by a series of bolts 3 passing through suitable holes in the sides of the casing and the bar. This bar 2 W111 preferably be inserted endwiseof the casing l,

the bar being provided with agroove i at each side vinto which extend tongues 5 stamped out of the sides of the casing. The

, tongues 5 will preferably be stamped at each the cable.

bar 2 is in position. This bar 7 ,it will .be noted is tapered from end to end.

Below the bar 6 is positioned the wedge member 8, which is provided with. a concave under'surface to substantially vfit the con tours of the cable. 9.

The device is used by insertingthe end of the cable between the under side of the wedge member 8 and the bottom of the (me. ing. When the cable is in position the screws 6 are tighteneddown against the ,bar 7 to force the wedge member against the cable to prevent the latters withdrawal.

8, so that the more the wedge member is moved the. tighter is its grip on the cable.

As before stated, it is desirable in some cases tovhave additional security, and'when this is necessarythe cable is extended further than usual beyond the end of the bar 7,

and from this extending end the armoring or sheathing is removed exposing the core of The naked core 13 is then bent upwardly around an. arc-shaped guide 15 It will be noted that certain of these screws 14% are longer. than'the others, and slidable on these screws is a clamping plate 10, which is adapted to be forced by nuts 11 on the screws 14 co-clamp the core against the upper side of the bar 2. p

It will be noted that'the bar 2 is'somewhatof T-form, the arms of the T being adapted to rest on the tops of thesides of the casing.

At the outer edge of the-upper surfaceof each arm'ofsthe T is formed a rib or bead 12 to prevent the core 13. slipping from between the plate 10 and the top of'the bar 2. A separateplate 10 may be provided on each bolt 14 if thought desirable, and any number or any size ofthese' plates may-be used as may be necessary. The casing 1, bars 2 and 7, and wedge members may be of'any desired length to suit the requirementsof the case, and any number of bolts 3 and screws 6 may be used. I

The clamp will be suitably formed at its end so that it may be secured to a post or other support.

If desired the bottom of the casing 1 and the under surface of the wedge 7 may be provided with suitable ribs and grooves to give them a better grip on the cable. As the armoring of the cable is usually in the form of a helix, these ribs and grooves will also preferably be of a suitable shape to match the helix of the cable.

From the above description it will be seen that I have devised a strain clamp which will satisfactorily attain the objects or my invention as set out in the preamble of this specification.

lVhat I claim as my invention is 1. In a strain clamp for cables, the combination of a channel-shaped casing; a bar lying between the sides of said casing; bolts passing through the sides of said casing and said bar to clamp the latter in position; a clamping bar below said first mentioned bar; and means engaging both sides of said bar for actuating said clamping bar to grip a cable.

2, In a strain clamp for cables, the combination of a channel-shaped casing; a bar secured in and closing the open side of said casing; a tapered clamping bar below said first mentioned bar; awedging member adapted to fit below the clamping bar; and means for actuating said clamping bar to grip a cable between the wedging member and bottom of the casing.

3. In a strain clamp for cored cables, the combination of a channel-shaped casing; a member supported by the sides of said casing; a screw threaded through the member by means of which a cable may be clamped against the bottom of the casing; and means for independentlygripping the core of the cable.

. 4. In a strain clamp for cables, the combination of a channel-shaped casing; a bar secured in and closing the open side of said casing, said bar having a groove formed in each side thereof and said casing having projections formed thereon engaging in said grooves; a clamping bar below said first mentioned bar; and means for actuating said clamping bar to grip a cable.

5. In a strain clamp for cables. the com bination of channel-shaped casing; a bar secured in and closing the open side or said casing; a clamping bar below aid first mentioned bar; screws threaded through the first mentioned bar and adapted to engage said clamping bar, a core clamping plate slidable on one ofsaid screws; and a nut on said screw adapted toforce the clamping plate towards the outer surface of the first mentioned bar.

6. In a strain clamp for cables, the com"- bination of a channel-shaped casing; a bar secured in and closing the open side of said easing; a tapered clamping bar below said vlirst mentioned bar; a wedging member adapted to fit below the clamping bar, screws threaded through the first mentioned bar and adapted to engage said clamping bar; a core clamping plate slidable on one of said screws; and a nut on said screw adapted to torce the clamping plate towards the outer surface oi? the first mentioned bar.

7. In a strain clamp for cables, the coinbination of a channel-shaped casin a bar secured in and closing the open side of said casing said bar having a groove formed in each side thereol and said casing having projections formed thereon engaging in said grooves; a tapered clamping bar below said first mentioned bar; a wedging member adapted to fit below the clamping bar; screws threaded through the first mentioned bar and adapted to engage said clamping bar; a core clamping plate slidable on one of said screws; and a nut on said screw adapted to force the clamping plate towards the outer surface of the first mentioned bar,

8. In a strain clamp for sheathed cables, he combination of a channel-shaped casing; bar secured in and closing the open side said casing; a clamping bar between said i st mentioned bar and the bottom of the channel-shaped casing; screws passing through the first mentioned bar and adapted to engage the clamping bar to clamp a cable between the clamping bar and the bottom of the casing; a clamping plate slidable relative to one or saidscrews; and a nut on said screw adapted to "force the clamping plate towards the outer surface of the first mentioned cable for clamping the cable core between the plate and first mentioned bar, said bar being provided with a rib to prevent side slip of the core.

9, In a strain clamp for cables, the combination of a channelshaped casing; a bar closing the open side of said casing; bolts securing said bar in position in the casing, said bar having a groove formed in each side thereof and said casing having proiections formed therein at each side between each of said bolts; a clamping bar below the first mentioned bar: and screws threaded through the first mentioned bar and adapted to engage the clamping bar.

10. In a strain clamp for sheathed cables, the combination of a channel-shaped cas ing; bar secured in and closing the open ide of said casing;' a clamping bar below aid first mentioned bar; means for actuat- :ng said clamping bar to grip the cable, said clamping bar having an arc-shaped guide at one end around which the core of the cable may be led to the top of the first mentioned bar; and means for clamping the core against the top of the first mentioned bar.

11. In a strain clamp for sheathed cables, the combination of a channel-shaped casby means of which a cable may be clamped against the-bottom of the casing; and means for independently gripping the core of the cable against the top of the said bar.

12. In a strain clamp forsheathed cables, the combination of a channel-shaped'casing; a bar secured between the sides of said cas- .of July; 1922. Y

THOMAS H. BARNARD.

carriediby the rew for independently gripv I I it the said bar. v

Signed at Toronto, Canada, this 18th day ping the core of the cableagainst the top of 

